Automatic telephone system



Nov. 11,'1924. 1,515,361v

w. T. pwELl.

AUTOMATIC TELEPHONE SYSTEM iledlSept. 6, 1919 o GROUPS 2O GRouPs 4-2 Lmes EACH '1 LINEA rlrwlns EACH 1 TRUNK FMUERS EACH.

4 Sheets-Sheet l 2O GROUPS A 2.0 GROUPS ALLOTTER PER GRODP 2.0 GROUPS l SEL PRESELECTOR PER GROUP INVENTOR WIHFRED '1'. POWELL ATTORNEY Nov. 11, 1924- 1,515,361l

, w. T. POWELL AUTOMATIC TELEPHONE SYSTEM ze ggc'issept. 6. 1919 l4 Sheets-Sheet 2` |z .sanza-ron Fumare: :Aca Z3 GROUPS :54 e v CONNECTORS EAC H.

Bev-ne mme coNTAcn-s) CONNiCT DR PRESELECTOR.

INVENToR W\NFRED T. POWELL.

ArroRNEY l l M Nov. 11, 1924. 1,515,361

v W.,T. POWELL 'v AuroMATIc TELEPHONE SYSTEM Filed sept. 6. 1919 4 sheets-sheet 4 CONNECTOR BHK.

CONNECTOR. l

SELECTQR 1.1NDER- ELECTOR "E INVENTQR v wmf-Rauw POWELL.

CONNECTOR PRESELECTOR.

Patented Nov. ll, i924.

isi

WINFRED T. POVFJ'ELL, ROCHESTER, NE YORK, ASSIGNOR T0 THE' STROMBERG- GARTSON TET.F"PEONE "Pff/3 NUEACTURENG COIi'ililIY, OFF RCHS'IER, NEW YORK, A

CORPORATION OF NEWT YORK.

AUTOMATIC TELEPHONE Application filed September To all whom muy conce/ai.'

Be it known that l, Winnen T, PownLL, a citizen ot the United States, residing); at Rochester, in the county of Monroe and State of New York, have invented certain new and usei'ul improvements in Automatic Telephone Systems, ot which the tollowing is a full, clear, concise, and exact description.

Thisy invention relates to telephone systems, and more particularly to telephone systems employing automatic switches in establishing' connections between telephone lines.

It is the lurpose ot' the present inifention to provide an automatic telephone system in which all the automatic switches are of the single motion type wl'iich may he ot the same structure and in which a minimum amount of apparatus is employed. ln accomplishing' this result the numerical switches have no hunting` movement, hut instead a backward hunting or iinder switch connects an idle numerical switch to a. point designated hy the preceding' automatic #itch in the chain. in order that it need not he necessary to wait for these various `finder switches to complete their operation, a temporary icy-path connects each numerical switch to the trunk circuit selected hy a preceding numerical switch, and when this trunk is extended hy mea-ns of the finder to the point designated hy the selector, the temporary hy-path is disestahlished'.

Other features not specifically named will appear from the following; detailed description and appended claims. t

Referring to the drawings, Figs. l and 2 with the Fig. at the riejl'it ot Fig. l, dia- `graniniaticallyY represent the `grouping arrangement ot the telephone lines and the various switches co-operatingr to interconnect said lines.

Figs. 3 and d when arranged in the order named, diagramma-tically represent the circuitdetails ot a train of switches employed in establishing' a telephone connection from one line to another.

For purposes ot this disclosure a telephone system having 840 lines has heen lects any one of seven'link circuits tor interconnecting the calling line and the previously seized selector switch. Each ot the seven linl circuits terminates at one end in a line vfinder switch, and at its other end in a trunk AEnder switch.

For operating; purposes the present system may he considered as being divided into two large groups, that is, 4t2() lines in each groupu For each group there are provided forty selectors, so that tor this system eighty selectors are provided. its soon as one of the forty selectors of one ot' the groups is taken for use, a connector pre-selector of which there are titty-eight or twenty-nine for eachl group, extends the connection hyv mea-ns ot a oy-path to the connector switch 'taken tor use. A selector nder switch ot which there is one i'or each connector', completes the connection from the connector switch which has heen seized for this connection to the trunlr that has heen taken for use.

r'ifhe various switches mentioned, namely,

the line finders, trunlr finders, selector lind-` ers, controllers, selector and connector switches, allotters, selector pre-selectors and connector pre-selectors may he ot.' the liat rotary type, that is, a switch in which the contacts are arranged in an arcuate contact bank and whose hrushes are advanced pro- `gressively over these contacts in a step-hystep movement hy pawl and ratchet mechanism under the control ot' the motor magnet All ot' the mentioned switches, except the selectors, connector switches and controllers, have no release mechanism lout remain in engagement with the contacts last used, The selector, connector and controller switches, however, are provided with a release magnet and other mechanism ttor restoring` tlP-.ese switches to normal at the time when a connection is heingj broken down. These various switches need not all he provided with the same number of contacts, hut

some of them may be ol smaller capacity than the others as Will be readily apparent. rThe numerical sivitches oi? this system are arranged to operate on the cumulative method, that is, they are directively operated in repsonse to several series ot impulses, the switches adif'ancing a number oli' steps equal to the sum of the number o'l'v imgulses in the various series. For example, it it is desired to advance a switch to the i'tteent-h contact, a series oi twelve impulses is sent followed by a series of three impulses.

rlhe present system has been designed to use an impulse transmitter to transmit twelve different series oi' impulses, but 'it will be readily understood tha the invention can be readily arranged to employ the impulse transmitter now commonl in use. The impulse transmitter disclosed, is arranged to send a series ot ten impulses, numbered from l to O and in addition tivo other series of impulses having twelve and twenty impulses respectively.

Let it be assumed that a call originates in some one of the forty-tivo lines et' the lirst group herein designated fr. bypath previously extended to all the lines ot' this group is completed from this calling line over conductor 6 to the selector preselector 7, individual to this group of lines.

This pre-selector through its brush 8 and multiple contacts 9 and conductor lO, comn pletes the by-path from the calling line to the trunk 11 individual to some one oi the group of forty selectors that has been taken lor use. The allotter indicated by the brush Y12 has previously operated to preselect some one of the seven link circuits individual to this group of 42 lines, and as soon as the link 155 has been selected, its line linder switch la hunts for the calling line, and its trunk iinder switch l5 hunts for themultiple contact 16 of the trunk ll previously selected Jfor use. 'lhe selector switch l? which has been seized is then directively operated by the calling party to select one ot the groups oii connectors in which the called line terminates. is soon as the selector completes its operation, the connector switch which has been taken for use is operated over a by-path completed over conductor 18, connector pre-selector 19 and conductor 20, and it is subsequently oper ated over a circuit including the selector .finder 2i and conductor 22.

ritter this brief description oi the layout of the system and the description ot the apparatus employed, let us turn to a con sideration of the method of establishing a connection from a calling` telephone line the substation oi which is indicated at ik to a called line, the substation oic Which is designated 13. In initiating a call, the calling subscriber removes his receiver 'troni its switchliook and adjusts the dial oi his sending device in accordance with the lirst digit of the Wanted number. On the torivard movement of the dial a circuit is closed from ground, through the shunt-ing spring 25, through the transmitter and sWit-chhook contacts, armature and back contact of the cut-oil relay CO, Winding of the slow-releasing line relay LR, through its continuity spring 26 and contact, armature and back contact of relay 27, and back contact and armature of trie motor magnet 28 of the selector pre-selector to grounded battery. he linerelay LR is energized'in this circuit but the motor magnet remains inert When in series with the line relay. The line relay LR attracts its armatures and at its outer right hand armature indicates a stopping point vfor the line finder switch and at its inner right hand armature and continuity spring 26 closes an operating circuit for the relay 27 in series with the line relay Lit. The relay 27 on attracting its armature, opens the operating circuit ot the motor magnet 28 ot the selector pre-selector, but closes a break point in the energizing cir cuit olf the relay 30. At the inner lett hand armature and iront contact oi the line relay LR, a circuit is closed from groun l, shunting spring 25, conductor 35, selector preselector brush 36, conductor 37, winding oil: the stepping' relay Slt to grounded hat tery. rl`he stepping relay SR attracts its ari'natures, and at its lett hand arn'iature and liront contact closes an energizing circuit or the slovv-releasing relay 38. rthis relay attracts its armatures and opens the operating circuit of the release magnet 39, and closes a break point in the operating circuit of the motor i agnet 40 otthe controller, from grounded battery, Winding, back contact and armature of this motor magnet.. Wiper il in its lirst position, right hand front contact of stepping relay SR, right hand front contact and armature o't relay 38 to ground. The controller is thus advanced one step and its 0H normal spring UN is brought in engagement with its con tact 34.

The impulses corresponding to the first digit of the Wanted number may now be transmitted over the circuit just described :tor the stepping relay SR, and in the mean time the allotter will designate a link circuit Ytor connecting the calling line to the selected trunk. The allotter is operated in the lolloiving manner As soon as the controller moved to an ofi normal position, circuit is closed for the relay 30 oiE the allotter from grounded battery, Winding of the magnet 29, Winding ot' the relay 30, iront contact and armature of relay 2'?, brush Si, conductors 32 and 3B. con-- tact Se. and off normal spring to ground. Relay 30 is energized in this circuit and attracts its armatures, but the motor magnet lOO 29 will not operate in series with the relay 30. However, if the brushes ot the allottcil are standing in engagement with the contacts of a link circuit that is in use, relay 30 will not be energized but the motor net 29 of the allotter will be operated in a circuit traceable 'from grounded battery, winding, bach contact and armature ol this magnet inner right hand contact and armature ot relay 30, allcttcr brush 42, lower front contact and armature of relay 43, trunk finder brush 44, conductor to ground at a contact similar to 34 and ott normal spring. rllhe motor magnet 29 will continue to advance until its brush 42 'tails to be connected to ground. his condition will indicate that the link with which it is in engagement is idle. The line finder and trunk Jnder individual to the allotted linlr circuit will now be advanced, the line finder to lind the calling line and the trunk finder to lind the trunk that has previously been taken for use in this call. The line inder operated over a circuit extended from grounded battery, left hand front contact and armature of relay 30, allotter brush 45, winding, armature and back Contact ot the line inder motor magnet 46, line linder brush 47, to ground at the back cont-acts and armatures of line relays associated with neu-calling lines. The calling line has its line relay attracted so that the energizingv circuit or the motor magnet ot' the line finder will be interrupted as 'soon as the calling line is reached. The trunk 'li s is operated over a circuit completed nic i grounded battery. resistance, outer right hand front contact and armature ot relay 30, allotter brush 48, winding of the motor magnet 49 ot' the trunk iin der. armature and hack contact of this magnet, and allotter hrush 50 to ground. The trunk finder advances its brush stepeby-step under the control ot its motor magnet until its test brush encounters a grounded test 'terminal which ground is applied through the brush of the selector pre-selector and indicatey that the trunk finder has reached the trunk which has been assigned for use. is soon as the test brush 5l encounters a grounded (est terminal, the motor magnet 49 ot he trunlz finder is shnnted by relay 53 and this relay is energized and attracts its armatureJ When the line linde:- has completed its operations, a ground potential will he absent on line linder hrush 47, and relay will be actuated at the close ot the operations of the trunk finder, so that switching relay 43 is now operated in a circuit trein `sounded battery, lett hand front contact and armature of relay 30, allotter brush 45, winding of magnet 46, armature and bach: contact of this magnet, upper winding ot relay 43, front contact and armature ot' relaiv to ground. rllie cut-off relay C@ individual to the calling line is now operated in a circuit completed from grounded battery, winding of this relay,` brush 54 of the line finder, lower winding and front contact of relay 43, trunk linder brush 44, conductor 33, contact- 34 and oft normal spring to ground. The cut-oill relay C() attracts its armature to disconnectthe line relay from the calling line, and the switchingrelay 43 closes break points in the two sides of the link circuit taken tory use, vso that the impulses from the impulse transmitter which previous to this time passed over the lay-path already mentioned, `will now be transmitted over the upper side oit the link circuit connecting the calling line and the selected trunk. @n the operation oi. the cut-oil relay, the line relay releases, which releases relay 27 and the selector pre-selector preselects a selector to be used in the next call. Relay 30 releases and closes a circuit `from ground at contact 34, contact of relay 43 and brush 42 to advance the allotter,y thus allotting the next linlr to be used. ln the event that the selector pre-selector had been in engagement with a busy trunk when the call was originated, ground over con'- dnctors similar to 32 and 33 would shortcir uit the line relay LR and since relay 27 would not be energized the motor magnet Q8 would advance the selector pre-selector until an idle selector is found.

it will ha, remembered that as soon as the .selector was seized 'For use, its controller advanced its wipers into their second position and subsequent impulses correspondinlfj te the rst digit oi the wanted number 'were transmitted over the by-patl1 extending tro-1n .ie calling' line to thc, selected trunk, or over ie allotted link circuit connecting the calling line and trunk. Vliti thecontroller in its second position, the stepping relay ribrates its armatures in response to the iii series of impulses and the motor magnet ot the selector is operated in a circuit closed from grounded battery, winding of this niagnet conductor 57. controller wiper :'58 in'its second position, slow-releasine relay 59, bacir contact and armature of stepping relay Fill, "u nt Contact and armature of relay 38 to Iground. The motor magnet .'36 advances the brushes ot the'selector one step tor 'fh iin-- pulse transmitted in this series. The motor magnet 40 oi1 the controller is maintained energized at the 'lront contact and armature ot the slow-releasing relay 59 during' 'the transmission ot this series of impulses, but at the clos-e of this series of impulses this motor maa net deenergizcs and advances the controller nipers into their third positi n. ln response to the next series of 'impulses cofesponding to the second digit of the wanted number, the selector continues to advance its brushes in the same'direction as in response to the lirst series ot impulses,

In this instance as before, the motor magnet 56 of the selector is controlled at the back contact and armature of the stepping relay SR and advances its brushes one step in response to each impulse received by this last named relay. The motor magnet i0 of the controller is again maintained energized at the front contact and armature oi' the slow releasing relay 59 during the transmission of the. second series of impulses, and when the relay 59 deenergizes at the close of this series of impulses, the motor magnet 41.6 de energizes and advances the controller wipers into their Jfourth position. lt should be understood that the selector brushes instead of being advanced directively to select a group and then being operated automatically to selec-t an idle line in the group, in the present instance the selector is operated on the cumulative arrangement, that is. it is advanced directively in response to several series of impulses and then a hunting switch operates to connect a succeeding` numerical switch to the contacts designated by the selector switch.

lhen the stepping relay Sli retracts its armatures in response to the iirst impulsel of the series correspondingto the third digit of the wanted number, the motor magnet l() is then energized in a circuit Yfrom grounded battery, winding, hack contact and armature or' the motor magnet 40, controller wiper ell in its fourth position, back contact and armature of the stepping relay Slt, Jiront contact and armature ot relay 3S to lground to advance these wipers into their ritt-h position' At:` the close ot this impulse. the stepping relay SR attracts its armatures again and the motor magnet 46 is now energized in a circuit closed at the Atront contact and armature of the stepping relay Slt, and almost immediately interrupts its own circuit to advance the controller wipers into their sixth position. lt Will thus be seen that the irst impulse of the third digit is lost, and the numbering of the lines at the connector must be arranged accordingly. lV ith the controller wipers in-position sia: and when the selector brushes have been set, a circuit is closed from ground. corr troller wiper 60, back Contact and armature of relay 61, conductor 62, winding of relay 63, continuity spring and Contact 64E, selector' brush 65, armature and back contact. ot relay 66, armature, back contact and windingl ot the motor magnet 67 off the connector pre-- selector to grounded battery. The relay 623 is energized in this circuit and attracts its armatures, thus closing a substitute locking circuit for itself from grounded battery, winding, back contact and armature oi the motor magnet 67, winding of relay 66, selector brush 68, inner armature of the relay 63, continuity spring 64e over the remainder of the circuit previously traced. The relay 66 is energized in this circuit, but the motor magnet 67 is not actuated at this time. At the right hand armature of relay 66, a ground is supplied to lock out other relays like 63 and an energizing circuit is completed for relay 76, while at the lett hand armature and Ytrent contact of the relay 66, a circuit is closed from grounded batter-,yg resistance, connector pre-selector brush 69, winding ot the motor magnet 7 O ott the sclector finder, and connector preselector brush 71 to ground. The motor magnet 70 advances the brushes of the selector finder to extend the connector to the trunk that hasl previously been selected. As soon as this point is reached, the switching relay 72 is actuated in a circuit completed from grounded battery, resistance, armature and front contact olf relay 66, connector pre-selector brush 69, conductor 73, upper Winding ot relay 72, selector finder brush 108, selector brush 7&1, outer 'iront contact and armature ot relay 63 to ground. Relay 72 attracts its armature and closes a locking circuit tor itself from grounded battery through its lower winding. iront contact and armature 75 of this relay. right hand front Contact and armature of relay 76 to ground. As soon as the switching relay 72 is operated. a circuit is closed from grounded battery. through the winding oif relay 61, conductor 7 6, selector vfinder brush armature 79, contact of relay 72, conductor 80, lett hand trout Contact and armature of relay 76, connector pre-selector brush 81, right hand armature and front contact of relay 66 to ground. rlhe relay 61 attracts its armatures and at its right hand armature closes a locking` circuit for itself, and relay 76 through contact 34 and its oli normal spring. At the left hand armature and back contact of relay 61, the holding circuit for the relays 63 and 76 is interrupted permitting these relays to retract their armatures.

As soon as the relay 66 retracts its right hand armature, the motor magnet 67 ot tlu` connector pre-selector is actuated to preselectthe nent connector to be used in `its group. This circuit extends from grounded battery, winding of the motor magnet 67. its back contact and armature, back contact and armature of relay 66, connector pre-selector brush 81, left` hand armature and front contact of relay 76 lo ground at contact 3-l and its off normal spring (Fig. 3). It will be remembered that as soon as the controller moves its wipers into position six, the relay 63 ot Fig. 4L is operated to close a by-path circuit V4for the motor magnet 83 of the connector from grounded battery, winding of this magnet. conductor 84, connector pre-selector brush 65, selector brush 86, left hand armature and front contact ol relay 63, conductor 87, controller wiper 58, relay 59, back Contact and armature ot relay SR, tront contact a nd ing position as in the case Where an idle line armature oi relay 38 to ground. The iaipulses corresponding to the third digit .t the Wanted number are transmitted over this circuit until the selector finder has conipleted its operation, whereupon the impuls-es are then transmitted over conductor S8, selectorl inder brush 89, inner-most armature and front contact of relay 7:2. Winding' ot the motor magnet 83 to grounded battery.

At the close ci' the series of impulses cor responding to the third digit. 'the ino'y i magnet 10 ot' the controller which has l held energized at the armature oi relay deenergizes and moves the Controller sw Wipers into position seven. Tn this position the fourth series of impulses is transmitted to the motor magnet 83 of the connector over the operating; circuit last described. At the close of this last series ot impulses, the motor magnet l0 of the controller which has been held ene` ized ar the previous case at the armature et relay deenerpgiZ-es and moves the side si i Wipers into their eighth position. The n 'L'inal ringing trip relay 90 is non opera in a circuit extendingv from grounded b tery. resistance, ringing machine nene" designated 91. the lamp 92, Winding' or the tripV relay 90, controller Wiper in its eighth position to ground. The relay attracts its armature and closes a circuit from `ground through the controller Wiper l1 in its eighth position. armature, baalt contant and Winding' ot the motor magnet 410 of the controller to grounded battery. il@ the control ot this circuit the contr moves its Twipers into their ninth or to position. 1When the trip relay attra armature it closes a circuit from yuound through the right hand Winding ot relay E,

.conductor 94. selector inder brush 95. lower most armature and front Contact of relay 72, connector' brush 96, through the resistance representingv the cut-ott relaxv ot the called line. to grounded battery if the Wanted line is idle. The relay 95%- attracts its armature, and when the relay 90 reti-acts its armature a circuit is closed from ground, malte before break contact 97, armature. YFront contact and left hand lou resistance Winding of relay controller Wiper #t1 in its ninth position, armature. back c( and Winding` ot' the motor m net to ,grounded battery. Under the outro] or this last described circuit` the motor inarnet mores the controller Wipers into their tenth or ringing;- position.

ln the event that the Wanted line is busy. a reduced potential will be present ou its test terminal so that -when the test brush 9G of the connector engages it. the relai.Y 'll not be energized so that the contr ller hold its `Wipers in their ninth posi .n stead of moving` them into the tenth or r istested, ln case the controller Wipers are held in position nine, a busy tone is transmitted from the busy machine BZ through the controller Wiper 58 in its 'ninth position, to the calling line.

lt has been assumed that the called line is and that the controller is moved into its tenthk position. In this position ringing current is transmitted from the ringing machine 91, lamp 92, marginal ringing trip relay 90, controller Wiper 98 in its tenth position, through the train switches and Wauted substation., back to the controller Wiper 99 to ground. When the called party responds the trip relay 90 is actuated and at its armature and front Contact completes a circuit for thecontroller motor magnet 40 to move the Wipers into their eleventh or talking' position.

llhen it is desired to disestablish the' connection, the calling party replaces his receiver on its switchhook. This causes the stepping` relay SR tov retract its armatures and thereby interrupt the operating circuit of the slow-releasing relay 38. This last named relay then retracts its left armature to close an operating circuity for the release magnet ott the controller from grounded battery, Winding oit this magnet, left armature and bach contact of the relay 38, conductor 33, contact 84 and ott1 normal spring to ground. The release magnet 34 restores the controller to its normal position at which time the oli normal spring engages its contact 100, and closes a circuit from ground over conductor 101, contact 102 and off normal spi-ing, Winding ot the release magnet 103 of the selector to grounded battery. This restores the selector to its normal position. As soon as the contact 34: disengages the ott normal spring, the holding relays 61 and 76 are deenergized and relay 76 closes a ott normal spring, and Winding of the releaseA magnet 105 to grounded battery. nder the control of the release magnet 105, the connector is restored to its normal posi-- tion.

Talking' battery for the calling subscriber is supplied through the Winding of the stepping relay SR and through the Winding oi the impedance coil 106. Talking battery for the called subscriber is supplied through the windings ot the impedance coil 107.

lt will be rememberedthat the iirst im l pulse of the series corresponding to the third or tens digit oit the Wanted number Was used to advance t-he controller out of positions four and five. For this reason no numbers the tens digit ot which is one, are assigned to any telephone lines. The system, however, is so arranged that if the impulses corresponding to the third designation of the wanted number are 12 or 20 in number, the circuits of the connector will make up or create a new impulse to replace the impulse lost in moving the controller trom position tour to position siX. For this purpose the marginal relay 108 is connected to the eleventh contact designated on the connector bank, and when 12 or 20 impulses corresponding to the tens digit ot the wanted number are transmitted, the connector brush 109 will either come to rest on 0r pass over connector back contact 110, so that in either case circuit is closed for the marginal relay 108, trom ground, winding oi relay 108, contact 110, connector brush 109, lower-most front contact and armature oit relay 72 selector linder brush 95, conductor 94, controller wiper 41 in its sixth position, armature and Yliront contact ot motor magnet 40, and resistance to grounded battery. The marginal relay 108 attracts its arma ture and closes a, circuit trom grounded battery, windingot motor magnet S3 of the connector, armature and back contact oit this magnet, front contact and armature of mar- `ginal relay 108 to ground. Under the control ot this circuit the connector is advanced an additional step. rlhe relay 108 is made marbinal so that when two impulses are transmitted for the tens digit followed by ten impulses :tor the units digit in which case the connector is moved to its eleventh Contact, battery on the test brush 96 from the cut-ottI relay oli the wanted line will not energize the relay 108 and cause the connector to take a false step. Under the last assumption battery at the controller magnet l0 will not be applied to the marginal relay 108 over controller wiper 11, 'for at this time the controller will be in position seven, because the impulses ot the units digits ot the Wanted number have been transmitted.

Virhile the system has been shown and described to accommodate Sil-.0 lines and while it has been proposed to use an impulse transmitter arranged to send series ot' twelve imijiulsis. it will he understood that the num her of lines may be greatly varied without departing from the present invention, since it will be clearly understood that it the number ot lines is great ly diminished that the selector switch will he oii'iitted. and it the ninnber of lines is greatly increased an additional selector will he added. lt will also be readily seen thatthe system may be arranged to employ an impulse transmitter arranged to send series of ten impulses without departing` from the spirit ot the present invention. lt will also he obvious that the numerical switches may` be operated to select a group of lines. and subsequently select line from the selected. 1epoup instead et select' lines by the cumulative method What l claim is:

1. ln a telephone system. groups olt tele phone lines, a group ot trunks individual to each group oil' lines, link circuits tor intorconnecting calling' lines and trunks, each link circuit ternimating` at each end in a lnintiug switch, a. progressively operable switch 't'or assigning link circuits for use. neans tor .issigning an idle trunk iter use? and means tor extending` a signaling circuit i'roiu a calling` line 'to the assigned trunk while said hunting` switches are operating.

ln a telephone system, groups o t tclephone lines7 a group ol trunk lines individual to each group of lines, link circuits tern'iinatingg; at each end in a hunting;l switch and serving t'o connect calling; line with an cned trunkn a progressively operable switch tor asswning link circuits tor use. and means tor assigrningi` an. idle trunk Lor use antiv ior extending a temporary sipnalin cl` c lcuit trom a calling' line to the assigned trunk while said limitingl switches are beine; operated.

il. ln a lelephrjine system. a plurality ol' isrcfups of telephone lines, a group ot' trunks individual to each group oit lines `tor extend inc; any one oi' the lines ot a rroup as a ailing line. hunting` switches i'or locating cali' lines and connecting them to idle trunks) means for allotting` trunks ttor use. a temporary signaling circuit lor connecting' a calling line to a 'trunk while the huntingV olnufating7 and means effective Ytor extending said signaling cir an as. igncd trunk.

. ln telephone system. a. plurality ol" f'='oups o t telcilihone lines. a lgroup ot trunks iuiiii'idual to each Igroup oit lines tor extend ing` any one ci thev lines ol a group as a ral ii r luie. huiniugswitches Ytor locating;` calli ngi lines and connectingv them to idle trunks.

nica-us toi' all'otcinu trunks toi' use. a temporary signaling" circuit :tor connecting a callY ingr lino to a trunk while its hunting switcl.

is operating. and means elifective thcreiittcr tor connecting` all idle lines oli a `group 'lo an assigned trunk hy way ol'Y said signaling).`

circuit.

ln a telephone system, a plurality ol' telephone lines. means including automatic switches 'fior interconnectingr said lines. sigg nailing' circuits over which said switcher: are rontrolled 'troni a distant point. inca l'or directively operating; said switches: over sail sigjialing` circuit to select desired zeji'oup m' succeeding' switches. means thereafter einer ating` to connect an idle switch in vthe sf lente' group to the switch which selected the "aux and temporary signaling circuits over which said idle switch is operated while said counection is being` completed thereto.

6. ln a telephone system, a plurality o telephone lines, a plurality oit numerical switches 'for completing` a connection between one telephone line and. another telelll) .lilll llt) phone line, and :i signaling circuit over which distant pointe a temporary branch signaling circuit also extending to ot said switches.

7. In a telephone system? an incoming' line terminating in a primary nun'icr'cal switch. a plurality ot outgoing lines tei-inn ot said certain rating in final numerical switches, means ttor operatint;l sail numerical. switches in response t'. signals i cm a distant point, link circa' extendingI said incoming line to any oi sai' outgoing lines through a tin-al numerical switch, means 'tor d gnatiugf a lin circuit, tor use. a nin-numerical switch indi. iduel to each link circuit Jor extending' said link circuit to said primary numerical switch, and a temporary signaling circuit completed about said non-nunierical itch dur g operation thereot.

ln 'i telephone systei 7 plurality ot' tele-phone lines7 a plural v ot trunk li si cach terminating' in au automatic sii'itffi7 ai'itoinatic switching;` means operating to oinucct a trunk to a calling' telephone line, a progressively operable switf'h for assit? trunks Jfor use` means tor a signaling circuit to an asi' about said ai'itoinetic switching' i'i'ieains.

9. ln a telephone system, a plurality ot' telephone lines, a plurality ot trunk lines each terminatintf in an automatic switch, automatic switchin means operating to con; nect a trunk to a calling line? a progressively operable switch for assigning trunks for usel` and means 'tor completinf.;v a ten'ipouary signaling' circuit to an assigned trunk about said automatic switching' means.

ttl. ln a telephone system. a plurality ot telephone lines, means including;` a chain ot' numerical and non-numerical switches 'tor interconnecting' any ot said lines with any other linea one ot said non-numerical switches being' interposed between two numerical. switches in the chain, and a temporary signaling' circuit completed about said non-numerical switch while it is being opcrated.

ll. In a telephone systenn a plurality oi telephone lines, means including a chain o'tl numerical and non-numerical switches for interconnecting' any ot said lines with any other lines., one saidv non-numerical switches being-g interposed between two nu merical switches in the chain` a signaling circuit having two paths ove. which said second numerical switch is controlled, one path ot said signaling` circuit being effective while said non-numerical switch` is being operated7 and the second signniliiigv path being' effective after said non-numerical switch has completed its operation.

12. ln telephone system, a plurality ot telephone lines. .impulse tra; nitting; devices connectable to said lines, primary and said switches are controlled 'from al ation ot said automatic switch.

13, ln a telephone system, incol'ning" lines, impulse transn'iit-ting devices arranged to 4be connected to said incoming lines, a selector switch and connector Switch, a testinga switch tor interconnecting an idle connector switchv and an actuated selector switcln andl a temporary signaling circuit extending about said testinaV switch while it is being` operated.

le. ln a telephone system, telephone lines, impulse transmittingv devices arranged to be connected thereto, impulse actuated select-ing' means and link circuits for extending` said telephone lines, a plurality oi associated independently operable switches electrically interposed hetwen the various impulse actuated means for testing preceding links in succession and interconnecting them', and a temporary signaling circuit extending about each ot said switches during the operation thereof.

la In a telephone system, incoming lines,

impulse transmitting; devices arranged to gbe ""100 i t i i' vices non-responsive to impulses trom said 100 impulse transmitting; devices operating' to select va previously actuated automatic switch, and a. temporary signaling circuit completed about said switching device dur ing its operation. l'

16. ln a telephone exchange system7 telephone lines serving calling and called lines7 impulse transmitting' devices associated therewith, link circu its each provided l with an impulse actuated automatic switch-Al ing` device, .interposed switching mechanisms non-responsive to impulses trom said impulse transmitting; devices for effectingl a connection between a calling' subscribers line and each successive link and its switching' device, and a temporary signaling circuit completed to the succeeding` link circuit about each automatic switching' mechanism during;- the operation thereof.

l?. ln telephone system, telephone lines serving' as calling and called lines, impulse transmitting' devices associated therewith, a trunk line, an impulse controlled selectory associated with said trunk, a connectorswitchv automatic for selecting a called line7 van 'interposed switch adapted to test for and interconnect the impulse actuated selector to the connector switch, and a temporary signaling circuit completed from said trunk to said connector switch before said testing switch has 4completed its operation.

18. ln an automatic telephone system, a plurality ot telephone lines, means tor initiating calls on said lines, means including' non-numerical switches` of the backward hunting type, numerical trunking switches and linal numerical switches tor interconnecting said lines and means tor pre-selecting said switches ahead ot the calls.

19. In. a telephone system, a calling' line, selector switches tor extending said line, controlling,` mechanism iter controlling the operation of said selector switches, a quiclr acting tinder switch responsive to the initiation of a call ou said line 'for associanim,` said mechanism therewith, means for subsequently associating` said mechanism vith said line, an impulse circuit established upon the initial association ot said mechanism with said line, a second impulse circuit. established upon the subsequent association. et said mechanism with said line, means controlled by the calling subscriber `for sending; impulses over both ot said circuits, and means responsive to such impulses tor setting said controlling` mechanism.

20. ln a telephone system, a calling; line, selector switches for extending` said line, cont-rolling` mechanism tor controlling the operation ot said selector switches, a quick acting` linder switch responsive to the initiation ot a call on said line 'for associating' said mechanism therewith, a main line finder ttor subsequently associating said mechanism with said line, an impulse circuit established `upon the initial association ot said mechanism with said line, a second impulse circuit establnhed upon the subsequent association ot said mechanism with said line, means controlled by the calling subscriber tor sending impulses over said lirst circuit while the main line finder is hunting,` tor the calling' line and tor sending' impulses over said second circuit atter said line is selected, and means responsive to such impulses for setting` said controlling); mecha anism.

2l. ln ay Ielephone system, a. calling; line, selector switches tor extending said line, controlling; mechanism tor controlling the operation `et said selector switches, a lint: circuit, means responsive to the initiation ot a call for connecting` said link circuit with said calling line and with said mechanism, a line finder switch 'tor subsequently associating said link with said line, an impulse circuit established upon the initial association ot said mechanism with said line, a second impulse circuit established upon the subsequent association et said mechanism with said line, means controlled by the calling' subscriber for sending impulses over said lirst circuit while said line linder hunting iter the calling` line and ttor senoing impulses over said second circuit after said line is selected, and means responsive to such impulses Ytor setting),q said controlling mechanism.

22. ln a telephone system, a calliue,` selector switches 'tor extending; said line, controlling mechanism iier controllingthe operation ot said selector switches, a quicl: acting finder switch responsive to the initiation et a. call on said line 'tor associating' said mechanism therewith, a main line finder toi" subsequently associating; said mechanism with said line, an impulse circuit established upon the initial association ol said mechanism with said line, a second ir pulse circuit established upon the subseqiul association et' said mechanism with said line. means controlled by the calling` subscriber tor sending impulses over said lirst circuit while the main line finder is hunting toi' the calling line and tor sending` impulses over said second circuit after said line is selected, means responsive to such impulses iter setting' said mechanism, and means iieetive upon the establishment ot said second impulse circuit for opening said first impulse circuit.

23. ln a telephone system, a calling line, selector switches tor extending,- said line,

'controlling mechanism tor controlling the operati-011 of said selector switches, a quick acting' finder switch responsive to the initiation ot a call on said line ttor associatinp,l said mechanism therewith, a main line vnder tor subsequently associating said mechanism with said line, an inipulse circuit established upon the initial association ot said mecha-- nism with said line, a second impulse circuit established upon the subsequent association of said mechanism with said line, means con trolled by the calling' subscriber tor sending impulses over said first circuit while the main line linder is hunting ttor the calling line and tor sending impulses over said second circuit after said line is selected, means Aesponsive to such impulses tor setting;` said mechanism, means effective upon the establishment ot said second impulse circuit 'tor opening said tirst impulse circuit, and means effective upon the operation ot the selectoi switches in accoroance with tie setting ci' said mechanism ttor opening said second im pulse circuit.

ln. a telephone exchange system, in combination, a trunk circuit includinp; a. pair ot normally open talkingconductors, aut-omatic switching apparatus accessible to one end therot, a linlr circuit tor connection with the other end thereof, an impulse sender associated with the link circuit, and means controlled by the impulse sender for closing),` the loo talking conductors of the trunk after the link circuit is connected therewith.

25. In a telephone exchange system, in combination, a trunk circuit including a pair of normally open talking conductors, a link circuit connected therewith, an impulse sender, means for connecting the impulse sender with the link circuit, and electromagnetic means for closing the normally open talking conductors operating in response to 10 the initial actuation of the impulse sender.

In witness whereof, I hereunto subscribe my name this 5th clay of Septembeil A. D. 1919. f

WINFRED T. POWELL. 

